Hardware?

Hello, I recently acquired a Thinkpad T400 with Libreboot and Trisquel 7 installed. It also has an Atheros AR5B95 wireless card. Basically my question is this: I want to have this machine be fully dedicated to Linux and FSF approved software. In general, I would like to add any additional hardware to it that will help it run better, and be as secure as possible. I know this is a wide question, but what are some hardware options I can add to it to help it be more secure and just plain run better and be fully dedicated to FSF and Linux? Go easy on me, I'm new to Linux so I apologize if this question is too general. Any help is appreciated.